In the present work, we demonstrate the ability to electrospin wheat gluten, a polydisperse plant protein polymer that is currently available at roughly 0.50 dollars/lb. A variety of electrospinning experiments were carried out with wheat gluten from two sources, at different solution concentrations, and with native and denatured wheat gluten to illustrate the interplay between protein structure and the fluid dynamics of the electrospinning process. The presence of both cylindrical and flat fibers was observed in the nonwoven mats, which were characterized using both polarized optical microscopy and field emission scanning electron microscopy. Retardance images obtained by polarized optical microscopy exhibited evidence of molecular orientation at the surface of the fibers. We believe that fiber formation by electrospinning is a result of both chain entanglements and the presence of reversible junctions in the protein, in particular, the breaking and re-forming of disulfide bonds that occur via a thiol/disulfide interchange reaction. The presence of the highest molecular weight glutenin polymer chains in the wheat protein appeared to be responsible for the lower threshold concentration for fiber formation, relative to that of a lower molecular weight fraction of wheat protein devoid of the high molecular weight glutenin component. Denaturation of the wheat protein, however, clearly disrupted this delicate balance of properties in the experimental regimes we investigated, as electrospun fibers from the denatured state were not observed.

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Current linear analysis is based upon the tri-linear model, which assumes a continuous and homogeneous porous medium within each flow region. This recent study, however, reveals that a discontinuous stimulated reservoir volume (SRV) is extensively associated with horizontal wells with fewer frac stages and/or within areas with high-stress anisotropic ratio. To characterize such isolated SRV scenarios, three parameters—fracture half-length, SRV permeability, and the half-width for each isolated SRV—must be inferred from the analysis, which creates a difficult challenge for the existing rate transient analysis (RTA) procedure. This paper presents a new RTA methodology and associated diagnostic plots to infer all three parameters simultaneously using the information beyond the linear flow period. The analyzed results illuminate optimizing the number of frac stages and well spacing. The newly developed "beyond linear analysis" procedure has been used successfully to analyze more than 100 Bakken wells with various completion types and frac stages. The resultant RTA-derived statistics have been used for the construction of type curves, well history matching, completion assessments, and optimal well spacing. Almost all the wells with fewer than 20 frac stages show an isolated SRV around each hydraulic fracture; these are good candidates for refrac. Although a high number of frac stages (e.g. >30 stages) will boost the initial production rate (IPR) and more quickly deplete the SRV, it is our conclusion that the estimated ultimate recovery (EUR) is not significantly enhanced beyond a certain number of frac stages. Moreover, both the incremental SRV and flow capacity associated with each additional stage steadily decrease. This suggests that there is an optimum number of frac stages and wells that maximize both the IPR and the EUR of a drilling spacing unit (DSU). This new RTA methodology allows, for the first time, detailed SRV and fracture description. The precise RTA model not only greatly relaxes the dependency on compaction and PVT properties suppression during the history match, but also clarifies the "stress shadow effect" from adjacent stages and the relationship between the shear fracture displacement/dilation and inter- stage intervals.